Method and means fob emitting sig



I '0ct.26,1937- I E.-R. PARsBER'e 9 63 5 'r'n VARYING SIGNAL HARACTERS' Filed Dec. 22, 1932 7 sheets-smal O t. 26, 1937. I an. PARSBERG 2,096,755

METHOD AND MEANS FOR EMITTING SIGNALS 'WITH, VARYING SIGNAL CHARACTERS 5:

Filed Dec. 22, 1932 Tsheets-wsheet 2 Oct. 26, 1937. v E. R. PARSBERG 2,096,755

METHOD AND MEANS FOR EMITTING SIGNALS WITH VARYING SIGNAL CHARACTERS Filed Dec. 22, 1932 7 sheets-sheet 3 1 EM" fizerzfia bw A Oct. 26, 1937. E, R, PARSBERG 2,096,755

METHOD AND MEANS FOR EMITTING SIGNALS WITH VARYING SIGNAL CHARACTERS Filed Dec. 22, 1932 7 Sheets-Sheet 4 W2 was "5% 1 "F I .i i H' -79 8 i1 fi" v gmnnioi Evil! 0 661; ZZZ/Mary,

'Oct. 26, 1937. 1 E, PARSBER'G 2,096,755 l METHOD AND MEANS FOR EMITTING SIGNALS WITH VARYING SIGNAL CHARACTERS Filed Dec. 22, 1932 v T "(sheets-sheets Oct. 26, 1937'. a. gpmsazae 1 7 METHOD AND MEANS FOR EMITTING SIGNALS WITH VARYING SIGNAL. CHARACTERS A Filed Dec. 22, 1952 7 Sheets-Sheet e i l/IIIII/I/IA I If iiafierffizrszem W Oct. 26,1937. PARSBER'G 2,096,755

METHOD AND MEANS FOR EMITTING SIGNALS WITH VARYING SIGNAL CHARACTERS Filed Dec. 22, 1932 "(sheets-she t v 1mm fir zag Patented 26, 1937 omen{s ruts THbpANn nANs roa'mn'n'mo sroi mus wirn-vaamo SIGNAL. cunn- AGTEBS I lirik' flobert l arsberg, Lidingo, near. stock ho l lnt Swedemassignor to-American Gu Accumula-, tor Company,"ltlisabeth, N. 1., a corporationof i Newtleney j Application December 22, 193mm atasha In Sweden-December 24,1931

" vide one flash every flveseconds for the marine trams which moves very much slower, the conclusion is easily arrivedat thatfor aviation the period should be quicker and not slower, and con sequently that a period of- 3, seconds would be 29 more in accordance with the requirement of the,

,airtraflicp 4 a V Flashes at shorter intervalsimay be obtained by increasing, the rotary speedof the apparatus or by dividing the available light energy into 5 several beamsn In both cases the emciency of the beacon will be reduced. 1nthe-flrst case thelight impression will be diminished owing .tothe re.- duced duration of-theflash (according toithe Blondel and Rey.law),- -while in the latter case the lightemciency of the beacon will be reduced by the said division of the light energy.

The Frenchmen Blondel and Rey have sclentiflcally provedthat in order to obtain aflashlight of-a light range equivalent-tothatof fixed light,

the light power of the flashlight must be-larger and must consequently be multipliedby a factor which is less than 1. This factor is dependent 'on the duration of the flash and diminishes quich lyas this is reduced. The factor in question is,

for instance, approx. .2' fora flash of .03 sec;.

.48 for a flash of .-1 sec.'and rises to .84 for aflash' of .3 sec.

From this point of view it would ,beadvanta- 45 geous in order to obtain a good'lightimpression or a good signal effect to have a long duration of the flash, whichcan be attained-by increasing the width of. the light beam or by reducing the r-' tary speed of the beacon. From the point'of 5 view of light economy the flrst mentioned way of solving the question is however not to be recommended. On the other hand atred'uction of the rotary speed will mean that the interval between the separate flashes willbe '1onger.-. As stated above it is, however, desirable that this interval should be comparatively short.

has been the practice for decadesof years to pro- It is thusevidentthatthe two requirements which at present present themselves particularly in the technique of airway-be'acons', i. e. long du ration of thefla'sh on the one hand andfshort; intervals-between the separate flashes on the other, are at variance with each other, inasmuch as the compliance with one of the requirements requires alow rotary speed'whereas the other requires high rotary speed of the beacon.

This invention refers to an arrangement by means of which the above mentioned features-are both attained simultaneously, the lens or reflector system of the beacon being so arranged 8810 11)- tate or oscillate with a revolving motion in such:

a waythat the signal character ofthe beanijor beams of light will be different-in different direc tions; According to'the invention this purpose is obtained thereby that the lens or reflector s'ys- 7 tem of the beacon is not; allowed to revolveuniiformlyas has been the practicehitherto; i. elj

with an approx. constant speed and all the time in the same direction, but is instead given'a non uniform revolving motion. By non-uniformree volving motion is to be understood in this connec-' tion that in certain-sections of the revolution the system either revolves at a slower speed thanin other sections, or else changes revolving direction,

i e. performs anoscillati ng motion' comprisin8 certain sections. j a '1 The intention with such a non uniform revolve: ing motion isto improve the light impression in certain sections of the revolution at theex pense oi the light impression in the other sections.

When the beacon is intended as an airway beacon the flying direction is suitably laid through the; first mentioned sections because the beacon light shouldfbe most visible in that direction whereas the" other sections do not as a rule requirej full light power.

In one form of employing the invention the lens or reflector apparatus is, as mentioned above,

given a lower angular speed when the'beam or beam of a light: sweep past the flying direction and a higher angular speed when thesame beams sweep past sections outside the flying direction. In this way the duration oithe-flash-time will be longer in the sections through which the'flying direction is laid, whereas it will be shorter in the other sections. -A beaconhaving two'le'nspanels arranged at an angle of- 180 between their ope"; tical axis, and giving" at a constant'revolvin speed and a period of, say, 5 seconds a flash of a duration of .10 sec., thus will be arranged sue-*1 Y cessiveiyto alter 'the revolving speed. When beams of light from the lens panels pass the flying direction the speed of the beacon has been reduced to one third, whereas the speed has been increased three times when the same light beams pass directions which are at right angles to the flying direction. Then the light'efliciency of the beacon in the flying direction will successively be increased by about whereas the light emciency in directions which are atright angles to the flying direction will successively-be reduced to about half. I Fig. l on the attached drawings shows a light eiflciency diagram of'such a beacon," i. e. a polar diagram, showing the effective light power or the light power, transformed according to the Blondel revolution but at constant angularspeed. a

J In the above given example the light efllciency curve will thus-have the approximate appearance oian ellipse, the major axis oil which, bb, is aboutthree times as long as the minor. axis o-c.- The aviator should naturally; try to keep the.

direction inwhich the flash is of the longest du-J ration..

'In another torm of employing the invention, suitably also arranged with 2 lens panels with 189' between the optical axis, the lens or reflector apparatus is given an oscillating angular motion in the horizontal level, whereby the light beams will sweep a certain section through which the flying direction is.laid.f.

Pig. 2 shows a digram of light eiflciency .and the light character oTa beacon, the revolving motion of. which comprises anangle of. approx.

'. The shadowed fleld inside curve e shows'the light efllciency, whereas curve I is a vector diagram by means of which the light character in different directions is easily read. If a. vector 0 is drawn this will intersect curve I in various 'points h, which correspond each to one flash.

The space between these points is proportional to the eclipses between the flashes. In the case shown it is thus seen that two flashes h are obtained in succession. separated by a slightly longer dark period. The closer you come to the flying direction i-i or i -i i. e. thei'sides of the revolving angle, the more'the two flashes will melt into one long flash h 0n the other hand, in thedirection of the bisectrix a light character is obtained in which the flashes recur at equal intervals. In this way the character of thebeacon can be read from the diagram in any direction.

The character of the beacon will thus alter during the revolving motion, single flash character-beingobtained in the centre of the section. From the centretowards the edges thesingleflash characterchanges gradually into a doubleflash character that becomes more and more pronounced, until thetwo flashesfollowing close on each other. melt into the long flash h at the extreme Eedges. The aviator should naturally try to fly in the direction in which the last mentioned long single-flash character is seen.

A larger orfsmalier improvement of the l ght 1-! of the angle economy is obtained depending on thesize of the angle or section that the beacon light has to sweep. If this angle is chosen to be 90 or V 01' a revolution for instance, as shown by Fig. 2,

an amount of. light is emitted within that angle which is 4 times larger than if the beacon were revolving 360, i. e. a complete revolution. This increased amount of light may be utilized to improve thesignal' eflect of the beacon either by increasing the duration of the flash or by reducing the'time between the flashes, or by both. The sections of the revolution that are not swept by'thesaid main beacon light lie outside the flying direction and should not require any lighting in normal flying. Should this be desired. however, in some case, a weaker secondary light can easilybe; arranged at k in the way known before.

' The revolving angle of the oscillating motion according to Fig. 2 can, if desired, be increased to If this is done and the-flying direction is laid along 'the'turn'ing points of the revolving motion single flash is obtained in the flying di rection, whereas double-flashcharacter is "obtained as soon as the aviator deviates from the flyinghirection; as will be understood from the diagram in Fig.2. -In order to avoid collision of meeting aeroplanes the aviator should in'thls casaalways keep tostarboard of'the beacon, i. e. the pilot should always keep inside the angle of the double-flash'charactenbm as near the direction of the single-flashcharacter as possible.

-The revolving angle may also be larger than 180, as shown by the diagram, Fig; 8. One of the diagrams, showing the light character of the two lens panels, is drawn with complete lines I, whereas'the other diagram, pertaining to the other lens panel, is marked with dotted lines mu Fromthis diagram it is exceedingly clear that in the angles.- I

which is swept by the light beams from both of the lenspanels, the flashes will occur twice as frequently as in the other sections. It a radius is drawn within this angle, the following char acter is obtained: two flashes following close on each other-one dark'period---two close flashesetc; The flying-direction is therefore-suitably laid within this angle a.

If the flying route is laid along one of the legs of the said angletwo aeroplanes coming'from opposite directions cannot collide, provided that both aviators keep inside the angle 1,111 which the close-double flash character of the beacon in front of themis seen. From Fig. 3 is also seen that the light efllciencycurve n in this case will be an ellipse.

In a third way of using theinventionthe lens or reflector apparatus is given a horiaontal revolving motion. which is discontinued oneor several times during each revolution, changing into an oscillating motion 'comprising a certain angle, thereafter to continue again as a revolving inotion. Fig. 4 shows a diagram of the light character in this case. As is seen, the o'scillating'motion takes place withinthe angle 5. In the centreof this angle three flnshes'i'ollowing in succession are obtained, which towards: the edges of the anglegradually change into one long and one short flash o and p, respectively. Outside thev angle p ordinary uniform "single-flash character is obtained. v I r The flying direction should be laid within the angle 5.

Fig. 5 showsadiagram accordingto whichtwo lens .or reflector apparatus placed,for instance,

on top of or beside each other move back and directions, as indicated by the light character curves 2 and z of the respective apparatus.

Single flash. with long flashes is obtained in the turning points z and z. of the revolving motion,

respectively, whereas a more or less pronounced double-flash is obtained between the turning points except at the centre of the angle, where single flash is obtained. 1

I Similar forms of employing the invention with' two diametrically bppositelight sections are particularly well suited for airway beacons placed along coasts where no light is desired towards the sea. i c I c In another form of employing the invention two lens or reflector apparatus are co-operating,

one of which revolves whereas theother turns back and forth within" an angle of any size, a s is shown by the curves 2 and z, respectively, Fig. 6, Within the revolving angle #01 the' last mentioned apparatus and outside this angle, respectively, difierent light characters may be obtained by'adjusting. the motion of the revolving lens apparatus in relationto the. oscillating motion, as is shown. to-the leftand to the right, respectively, in the 'diagramFigfi. From thediagr'rl'n to the left is seen that, the aviator receives a mixed single and double flasl'icharacter furthest out towards starboard and three-flash character furthest out towards the port side. Outside the revolving angle 1 a slow single-flash character is obtained in relation'to the character within the said angle. The revolving angle 7 is the limit of the flying route. "If the connecting line between two such beacons is laid along one of the-"legs 'of the revolving angle 'ythere can be 'no-collision of aeroplanes coming from opposite directions,

provided that the pilots always keepinside th 1 angle '7 of the beacon in front of them,

Inthis form oi.v employing the my ntio'nzthe character within theflyins angle 7 can be very rapid and alterations in the character are thus easily noticed. I s Q Lights of the description in question makethe use of special so'called course lights unnec.- essary'because the aviator will notice an altera-' tion in the flying character 'as soon as he"de-- viatesfrom the flying course. I I The above described forms of arranging the light may naturally also be used for maritime beacons, or for maritime and ,airylray beaconscombined. A

On, the attached drawings some constructive,

tioned invention are shown. The-first form of employing the invention, according to which the lens orreflector'apparatus revolves at a per odically varying angular speed, is shown in Figs.-

7-15. With such arrangements the efllciency diagram according to Fig. 1 is obtained. Figs. 16v and 17 show some forms of arranging so as tov provide for an oscillating motion comprlslnga certain angle, corresponding to diagram Fig-.fsL-2 and 3. Figs. 18 and .19'show an arrangement in orderto provide for,a horizontal revolving mo tion, which is interruptedand replaced in certain V I v e which is connected to thelens system and rests in a bearing at M.- Thctwo shaftsare connected which move in relation to each other, corresponding to the diagram'Fig. 5.. In the arrangement according to Figs. 21, 22, 23 thelens system is divided in two parts, one' of whichrevolves and the other turns back and forth within anangle of any size, corresponding to diagram Fig.3;

apparatus whereas Fig. 8 showsa horizontal seci I Fig.7 shows a verticalsection through a lens tion oi the same ap'paratusalong the line -A'CB.

Two lenses, for instance Fresnel lenses, l,'!, are

supported by afoundation plate lconnectedtoaa vertical revolving shaft 3.. Inside the lenses a source oflightls arranged in this case-consisting of an electric incandescent lamp'5;-the'light mam. I- which is refracted bythe'lense's l and 2 in such .a .way that. one beamof lightiis reflected from each one ofthe lenses, as indicated by the dotted lines. 0n theshaft 3,. resting in the. bearingii at the flxed'foundation-L'a revolvingscrew wheel 9 1 is placed, which gearswith a worml. The worm I is connected to a suitable source of power, for

instance an electric motor, which causes the worm to revolve at a constantspeed. As is shown, the screw; wheel 9 is cast in one'piece-with or in some other way connected to an excentric gearedelliptic cog-wheel l0 which is also placedon theshaft 3 and-'which'engages with an .excentric g'eared elliptic cog-wheel-ii of the same*si'ze,-this latter wheel, as well as a cylindrical cog-wheel it that is firmly secured to thecog-wheel I I ,being placed on an intermediate shaft arranged at the'iourn Islspeed, which aftergearing'to about half by means of the cylindric gear l2; I4 is transmitted to the shaft: andthe lens system connected to same. By the reduction of thezspee'cl, the speed cycle isrepeated twice. in each revolution of'the lens system, whereby, as shown by the diagram Fig. 1', minimum .and maximum value of the'light are at right angles" to each other.: l i

In orderto provide for thedesired periodically varying speed of motion. any-known arrangement intended for such purposemay be used.

Amongst the great .number'of such arrangements the following-additional examples may be mentionedhere: w w Fig. 9 showsa horizontal'section'ofia lens-sysa periodically varying revolving .motion is transefilciency willbe obtained in twoidirectionswhich 40 t tem similar to the, one describediabove, to which" mitted by means of a link mechanism. on the driving shaft, i5 a=iink I! is placedflon which there is agroove, l5. In this groove a journal for anotherllnk. i8v slides, this latter link I8 being placed one. shaft I 9 connected toth'e iens'system. If the-shaft, i5 is caused torevolve at a constant speed, thelinlr il will be'includedin this motion and the journal for the link I! will slide" back andforth in the groove 18 at the same time causing the shaft I! to revolve.- It is evident that this shaft will thereby be caused to revolve atape'ri I 'odicailyvarying speed,-seeing that its momentary" speed depends on theangle between the two links. J Fig-.10 shows schematically a- Cardanic link-"arrangernent serving the same purposeas'the'above described transmission mechanisms. The driving 1 shaft", resting in fixedb'earings 23, is arranged in ahinclined position in relation to the shaft 2| byr'neans oi auniversal joint-.12. 1 the shaft 2a is revolving at constant' speed the shait I will, o as is knowm-be calmed to'revolve-at a periodicallyf va yi pe d 7 Fig. 11 showsjchelnaticaliy another arrangement for transformation of a uniform revolving nation into a periodicallyvarying motion. On

i y va y n the driving shaft 28 a cog-wheel 28 is secured-in an excentric position, this cog-wheel engaging with a pinion II. which in its turn gears with a third cog-wheel I. placed on thev shaft 20 connected to the lens system. The pinion 21 is supported by two arms 8|, 3| turning around the cmitre of the pinion, one of these arms, ll. turning around a journal 32 in the centre of the wheel 26, whereas theother arm 8| turns around'the shaft ll. If; the shaft ll revolves at constant speed, the cog-wheel II will turn excentrically around this shaft, but the gearing with the intermediate pinion" as well asthe gearing between this pinion andthe cog-wheel 20 is maintained because simultaneously withthe rotation of the wheel It the pinion I1 is moved by means of the arm II. The

pinion 21 will thus roll back and'forthalong a part of the periphery of the wheel 2!. whereby this wheel will be caused'to revolveat a perispeed. If a suitable excentricity of the wheel Ills chosen and'the three cog-wheels areofsuitablesiaein'relationto each other this motion may abo be caused tochange direction A further arrangement for the same purpose ll shown in F188. 12, 13, 14 and 15. 113.12 is a verticalsection through a lens apparatus and the driving mechanism belonging to it,whereas mg. 13 is a horisontalsection through the latter along the line -D. 0n the driving shaft 82,

restinginabearingintheframe 'L adiskflis secured. in which there is a carnor guidinggroove 84. In this groove,- bordering on' the edge II' of the disk,-a roller ll slides which is ara I of the shame! acrank on shaft ll, connected to the lens apparatm. e crank II isxarranged above the disk. in wsythat'the crank does notprevent the Whenthediskllturnsata eonstantspeed the roller II is obliged to follow In the position of the disk and thecrank-l'l shown in-l"igs.- 12 and 13 the latter does not receive any revolving component of force whenthe disk- SI revolves. In order to move the crank out of this dead position a knob is arranged on the disk as, this knob co-operating with a corresponding knob II on the crank I! in such a way that when the disk .83 turnsthe knob ll causes the crank to leave the dead position. The

of the roller 38 in the-groove I will thereafterbesuchastocausetheshaftato revolve when thedisk It. turns. In order to make the roller continue to follow the groove at the apex of the "heart." when the disk SI has turned wheel ii the desired revolving move by means of the ample of an arrangement intended to provide -for an oscillating motion of the lens system. On

the driving shaft it a can disk 41 is placed, arranged in such a way as to guide an arm 4! secured on the shaft ll of the lens system. When the shaft 4! revolves the shaft 'w'ill'in this way be turned back and forth over a certain angle. Constant angularspeed may suitably be obtained if the cam disk 41 is shaped as an involute. If

the motion is desired to comprise a larger angle than 90' an intermediate shaft a should be By choosing a suitable relation between the Bear.

ing of the cogsed segment "and the cogged angle of the lens apparatus is obtained.

In Fig.16, the corresponding diagram of which is shown in Fig. 2, I2 is the lens for emission of the secondary light shown at k in the di ram.

An oscillating motion may naturally be obtained also in other known ways, for instance by means cfa crank and connectlng rod,'a crank and slot or the like which will be evident without any special'drawings;

Fig. la'shows an arrangement intended to give the lens apparatus a revolving motion, which porting the lens apparatus or bv means of a special friction clutch. The disk It is provided on the underside with a number of pins 80 spaced in a certain way, for instance two pins in diametrically opposite places. While the disk 58 is revolving these pins will be caused to co-operate in a certain position with a cam disk 6|,rotating in the same direction as the disk 58. Owing to this co-oper'ation the disk. I. will be moved back wards during a certain part of the revolution but will thereafter continue its original 'motionr During the motion backwards there will naturally be some slipping in the bearing 51. or in the friction clutch. The cam disk '80 is caused to shaft ll via three cogwheels I, 02, 63.

A similar motion can also be obtained by means of the arrangements shown in Figs. 11, l2, 13.

Fig. shows a lens apparatus cutln two halves.

by a horizontal plane through or nearv the focus of the lens system. The lower lens part ll rests on the disk 64, placed on the vertical driving shaft a CI. The upper lens part II is supported by the a is interrupted and replaced in a certain or cer- I rods '8 which are secured to a table 61 revolving around the shaft 65. On the shaft as and the table, respectively, the conical cog-wheels II and a 89 are arranged, which gear with a commonconical cog-wheel ll. If this latter cog-wheel is caused to revolve, the upper and the lower parts,

I4 and II, "of the lens apparatus .will revolve in opposite directions. A periodically varying motion may simultaneously be obtained byconnecting any of the above mentioned motion mecha! nisms to the shaft H of the cog-wheel ll. As is shown,this mechanism consistsin this case of an inclined universal joint.

By the said division of the lens'one common source of light may used, which is advantageous both from an economic point of view and from the point 'of view, of safety as compared to thearrangement hitherto used in such cases of prosecured to a table 61 revolving around the shaft [per lens part 14 are caused to revolve at a periodically varying revolving speed by. means of the elliptic gear l6, l1 driven by the shaft 15. The low- 7 er lens part 13 on the other hand is caused to move back and forth by means of the cam disk 18 arranged on the shaft 15 co-operating with the arm 65. The lower lens part I3 rests on the disk 64 placed on the shaft 65. The table 61 and the up- 19; secured on the shaft 85. Instead of these driving mechanisms some of the other arrangements previously described may be used.

Fig. 22 shows a section along the line GH,while Fig. 23 shows a section along the line 1-K in Fig. 21.

In the diagrams hitherto shown, at least one lens or reflector system rotates with a non-uniform speed. Indeed the same result also may be obtained by means of two or more lens or reflector systems, rotating with different speed or in different direction or both. In the diagram shown in Fig. 24 two lens parts placed, for instance, on top of or beside each other, are supposed to revolve in opposite directions but at the same speed. The light efficiency curve is shown at q, from which is seen that a very marked increase in the light range is obtained at q andq in which points of the periphery the light beams from the two lens parts coincide. The curve 1' indicates the light character of one of the lens parts, while the curve s indicates the character of the other part. It will be realized that double-flash is obtained everywhere except in the direction tt, where the light beams from the two lens parts coincide and where a long single-flash character is obtained. In addition, a twice as rapid singleflash character is obtained in the direction t-t at right angles to t-t, but in that direction the duration of the flash will only be half as long as in the direction t-t.

It is easy for the aviator to follow the exact flying route, which is suitably laid in the direction t-'t, with a deviation of a few degrees only, because as soon as he leaves the route, flying for instance to the right of it, he will-notice a light beam coming from the right first, quickly followed by a light beam from the left, i. e. doublefiash character will be obtained. If deviation takes place to the left, double-flash character is also obtained, but in that case the first flash will come from the left followed by a flash from the right.

The lenses may naturally also be made to revolve at different speed in opposite directions, as is shown in the diagram Fig. 25. As is seen, the light character will in that case be more complicated. u representsthe light character curve of one of the lens parts and v the curve of the other lens part. c I

According to the diagram Fig. 26 two lens parts are supposed to revolve in the same direction but at different speeds. a: and y, respectively, represent the light character curves of the two lens parts.- This diagram is peculiarthe respect that the same character is not obtained, in more than one direction. r

In the arrangements according 24-26 9 it is essential, that the values of speedsarein asimple relation to each other,e. g. 1:1,;112, 2:3 or the like. In this latter occasion, the speeds having a ratio of 2:3, the character willberepeated every second turning of the slower-apparatus and every third turning of thefaster apparatus. a

tion with beams vof all kinds. -He re the or beams of visible light has been shown, but it is assumed that equally well,-e. g. r a diovbeams or beams of other than visible light maybe transmitted in the same manner.

Having thus described my claim and desire to secureby Letters Patent is:

1. The method of producing signalswithdifferent signaling character in difierent directions, comprising the directional emission of a beam of radiant energy or the like from a source, rotating the directional emitting'means to produce rotary movement of the beam in a predetermined plane, and'periodically interrupting the rotary movement of said directional emitting means'and oscillating said beam in the same plane during the period of interruption.

2. In signaling apparatus, the combination of a source of radiant energy, projecting means for producing a beam from the energy emitted by said source and for directionally controlling said beam in a plane, means for rotating said projecting means about a flxed axis at right angles to the direction of said plane, and means for periodically interrupting the rotational movement of said projecting means and oscillating said pro-' jecting means about said axis.

3. The method of emitting signals with different signaling. character in different directions, which comprises projecting a beam of radiant energy or the likeirom a source, rotating said .beam around said source substantially in a plane,

interposed between said shaft and said support to reverse the rotary movementof said support from a certain position of its movement through a predetermined angle and thereafter continue the rotary movement past said position.

5. In signaling apparatus, a source of radiant energy, projecting means for producing a beam from the energy emitted-by saidsource and-for directionally controlling said beam within a plane, a rotary support for said projecting means, means for rotating said support in one direction about an axis at right angles to said plane and including a continuously rotating shaft, a friction driving connection between said shaft and said support, and means to effect slippage of said friction driving connection and periodically rotate said 10' Obviously the method of transmitting directed beams, above mentioned-can be usedin connecsupport through a predetermined angle in a (11-1 rection opposite to the direction of rotation of said shaft.

withsaidcameroove.s'aidgroovebeingaoshaped no to rotate and oecillate laid driven .nected between said I laid projecting and said'projecting nly William I elipp'egeoisaid couplingnndto're'vemtherotary means to eflcct slibwc or said coupling and thereby arrest the rotary movement or said proiecting mean; at predetermined 9. A beacon having a source of light, proiectingmeans for directing said light in a substantially horizontal direction in theionn'of a beam, a driving shalt, man: for continuously rotating said driving shaft in onedirection. niricizion coupling'interconnectedbetvnen'eaid drivlnglhait meam, periodiprojecting means to eilect movement of said proi cting m' du z'w i determined in Bonnier P. 

